Optical trapping and manipulation, which is the use of precisely shaped laser beams to hold, rotate, and measure microscopic structures, is reshaping how scientists explore the physical behaviour of living systems. These light‑driven tools allow researchers to quantify forces, observe rapid motions, and detect subtle mechanical changes inside cells at extremely small scales. Many of these measurements were previously out of reach, yet they are crucial for understanding how cells function, adapt and respond to stress or disease triggers.
At The University of Queensland, the Rubinsztein‑Dunlop lab is at the forefront of this work. Dr Mark Watson is one of the researchers expanding what optical tweezers can do, having recently completed his PhD, Mark is continuing to advance the methods. His specialty lies in rotational and ballistic optical tweezers, which are platforms that can track the rotation of microscopic probes at exceptionally high speeds. These techniques allow scientists to capture dynamic processes in cell‑like environments on millisecond timescales, revealing biological activity that happens too quickly for many conventional tools to detect.
A major focus of Mark’s research is improving how we measure the physical properties of tiny biological environments. Using rotational optical tweezers he has developed targeted approaches to measure the fluid properties within cells by using light to control and twist a microscopic spherical probe. These measurements reveal physical signatures that provide clues about how cells move, change shape and perform their functions. Mark’s published studies show these tools in action in living cells and soft biological materials, highlighting their potential to uncover early signs of changes linked to health or disease.
Mechanical properties inside cells, such as viscosity, stiffness and force transmission, are central to processes including cell division, development, immune responses and disease progression. Tools that can measure these properties directly and in real time give scientists a window into how life operates at the smallest scales. Mark’s work enables exactly this – fast, sensitive and minimally disruptive measurements that can capture the physical “early warning signs” of how a cell is changing. These capabilities are essential for studying disease mechanisms, testing drugs and uncovering how subtle physical shifts influence biological behaviour.
As QUBIC develops quantum‑enhanced sensing and imaging technologies, high‑precision optical trapping systems will form a vital bridge between classical photonics and emerging quantum tools. Mark’s improvements to stability, bandwidth and calibration help ensure these platforms are ready for integration with quantum light sources and quantum‑enabled readouts, future techniques that promise to reveal biological processes with unprecedented sensitivity.
Continuing as a postdoctoral researcher in the Rubinsztein‑Dunlop lab, Mark is now extending his work into new regimes where optical manipulation is combined with faster detection, new forms of structured light and emerging approaches from quantum photonics. The application of his research is guided by close collaboration with cell biologists across QUBIC to determine which biological problems to tackle and what further developments are needed. These developments will contribute directly to QUBIC’s mission to create the next generation of precision tools for understanding life at its most fundamental scales.
